OPTIMAL WEIGHT FOR REALIZED VARIANCE BASED ON INTERMITTENT HIGH‐FREQUENCY DATA*

Japanese stock markets have two types of breaks, overnight and lunch, during which no trading occurs, causing an inevitable increased variance in estimating daily volatility via a naive realized variance (RV). In order to perform a more stabilized estimation, we modify Hansen and Lunde's weighting technique. As an empirical study, we estimate optimal weights by using a particular approach for Japanese stock data listed on the Tokyo Stock Exchange, and then compare the forecast performance of weighted and non‐weighted RV through an autoregressive fractionally integrated moving average model. The empirical result indicates that the appropriate use of the optimally weighted RV can lead to remarkably smaller estimation variance compared with the naive RV, in many series. Therefore a more accurate forecasting of daily volatility data is obtained. Finally, we perform a Monte Carlo simulation to support the empirical result.     

ANTI‐DUAL OF ECONOMIC COALITIONAL TU GAMES*

Some well‐known coalitional TU (transferable utility) games applied to specific economic problems are shown to be connected through the relation defined as the anti‐dual. Solutions such as the core, the Shapley value and the nucleolus of anti‐dual games are obtained straightforwardly from original games.     

Debt Policy Rules in an Open Economy

In a small open economy model of endogenous growth with public capital accumulation, we examine the effects of a debt policy rule under which the government must reduce its debt–GDP ratio if it exceeds the criterion level. To sustain public debt at a finite level, the government should adjust public spending rather than the income tax rate. The long‐run debt–GDP ratio should be kept sufficiently low to avoid equilibrium indeterminacy. Under sustainability and determinacy, a tighter (looser) debt rule brings welfare gains when the world interest rate is relatively high (low).